Differential temperature valve with pressure override



F. X. CARTER Feb. 22, 1955 DIFFERENTIAL TEMPERATURE VALVE WITH PRESSURE OVERRIDE 2 Sheets-Sheet 1 Filed March 13, 1951 INVENTOR.

0 ATTORNEY Feb. 22, 1955 F. Y. CARTER 2,702,571

DIFFERENTIAL TEMPERATURE VALVE WITH PRESSURE OVERRIDE Filed March 13, 1951 2 Sheets-Sheet 2 E w E a a 2 3 a g a: n; j

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- INVENTOR. 31.444 64% BY MUM M Kg, ATTORNEY United States Patent DIFFERENTIAL TEMPERATURE VALVE WITH PRESSURE OVERRIDE Franklyn Y. Carter, Dearborn, Mich, assignor to Qetroit Controls Corporation, Detroit, Mich., a corporation of Michigan Application March 13, 1951, Serial No. 215,325

7 Claims. (Cl. 236-80) This invention relates to new and useful improvements in temperature operated valves and more particularly to a differential temperature valve for controlling flow of cooling water to the condenser of a refrigeratlon system. In many localities economy of cooling water for refrigeration systems is of great importance and it 1s highly deslrable to utilize to the greatest extent the cooling capacity of water which is used to cool refrigeration condensers.

Accordingly, it is one object of this invention to provide a temperature operated valve of new and lmproved construction.

Another object is to provide a differential temperature operated valve of new and improved construction wh ch is particularly adapted for controlling flow of coolmg water to a refrigerant condenser.

Another object is to provide a new and improved d1fierential temperature operated valve having a pressure operated safety means dominating the control of the valve.

Another object is to provide a pilot operated dlfierential temperature valve having a pressure responsive means operable to override the thermal actuator for the pilot valve for safety operation.

Another object is to provide a refrigeration system wherein the flow of cooling water to the condenser is controlled in accord with the heat requirements thereof and the outlet pressure from the compressor.

Another object is to provide a cooling system for a water cooled condenser of a refrigeration system wherein the flow of water is controlled in response to the dfierential of cooling water temperature at the inlet'and outlet of the condenser and the refrigerant pressure on the outlet side of the compressor.

Other objects will become apparent from t1me to time throughout the specification and claims as hereinafter related.

This invention comprises the new and improved construction and combination of parts which will be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly clanned.

In the accompanying drawings to be taken as part of this specification there is clearly and fully illustrated a preferred embodiment of this invention in which drawm s:

Figure 1 shows in central section this improved control valve and,

Fig. 2 shows diagrammatically a refrigeration system and the manner in which this valve is connected for use therein.-

Referring to the drawings by characters of reference and more particularly to Fig. 2 there is shown a refrigeration system having a compressor 1, condenser 2, rece1ver 3, expansion valve 4 and evaporator 5 connected in series with each other, the evaporator being connected back to the compressor. The condenser 2 is of the water cooled typeand is provided with cooling water throughinlet and outlet pipes 6 and 7 respectively, cold water flowing in the direction indicated by the directional arrows. Connected in the inlet pipe 6 to the condenser 2 is a temperature operated control valve 8 having temperature responsive bulb elements 9 and 10 responsive to inlet and outlet temperature of cooling Water to and from the condenser 2. The valve 8 is also connected by conduit 11 to communicate with high pressure refrigerant leaving the compressor 1 to provide a response by the valve 8 to re frigerant pressure. The valve 8 is set forth in detail in land its operation in the systemwill be described 2,702,671 Patented Feb. 22, 1955 'ice mopf: fully following the detailed description of the valve itse Referring to Fig. 1 it is seen that the valve 8 comprises a main valve casing 12 having an inlet 13 and an outlet 14 and having an internal partition 15 providing a valve port 16 and a valve seat 17. The valve casing 12 has a tubular extension 18 having a cylindrical bore or valve chamber 18 which there is positioned a cylindrical piston or valve actuator 19 operable to have reciprocal movement therein. The piston 19 is provided with a pressure equalizing aperture 19 and has secured at its lower end by a screw 20 a rubber or composition valve member 21 which engages the valve seat 17 when in a closed position. The upper open end of the casing projection 18 is closed by a pilot valve casing 22 which is secured to the casing flange 23 by a plurality of screws 24 only one of which is shown, a sealing gasket 25 being provided to seal against leakage. Within the casing projection 18 there is positioned a spring 26 which abuts the lower wall of the casing 22 at its upper end and the piston at its lower end to urge the piston 19 toward a valve closed position. The pilot casing 22 is hollow and is divided internally into two chambers 27 and 28 by a valve seat member 29. In the bottom wall of the pilot casing 22 there is provided an aperture 30 opening from the chamber 27 into the valve chamber 18 in the valve casing projection 18. From the chamber 28 a passageway 31 extends through the wall of the casing 22 and projection 18 of casing 12 to the outlet side of the main valve casing 12. The valve seat member 29 in the casing 22 has a valve port 32 provided therein which is closed by a pilot valve member 33 in the chamber 27. The valve member 33 is secured to and carried by a guide member 34 of generally rectangular construction which is longitudinally reciprocally movable in the cham of Fig. 2. -Within the cup-shaped casing there is positioned a pressure responsive bellows member 39 secured at one end and hermetically sealed to the plug member and having a disc-shaped head plate 40 at the other end thereof. The bellows head plate 40 is connected to a valve stem 41 for the valve member 33 and is biased to close the valve by a spring 42 compressively positioned between the bellows head plate 40 and the plug member 35. It should be here noted that the stem 41 is not connected to the valve member 33 but is engageable therewith and movable thereto by the bellows plate 4t). The valve casing 22 is also provided with an aperture 43 overlying the valve chamber 27. The aperture 43 is closed by an annular supporting member 44 on which there is pivoted as at 45 a lever member 46 having its lower end positioned in an aperture in the guide member 34 for actuation of the valve member 33. The casing 22 is further closed against leakage through the opening 43 by a flexible bellows member 47 which has its lower end secured to the supporting member 44 and its upper end sealed to the lever member 46. There is provided a T-shaped casing 48 which fits around and secures and seals in position the supporting member 44 and is held in position by a plurality of screws or bolts 49. The actuating lever 46 extends into the Tshaped casing 48 and carried on its upper end a thrust transmitting member 50 having oppositely alined recesses 51 and 52 receiving the pointed ends of thrust rods 53 and 54 respectively. Extending from one leg of the T-shaped casing 48 and threadedly carried thereon is a tubular supporting casing 55 carrying on its end a thermostatic power element generally designated 56. The power element 56 comprises a cup-shaped casing 57 having sealed therein a pressure movable bellows 58. The bellows 58 has a cup-shaped end wall 59 in which is secured one end of the thrust rod 53. There is also provided a rod extension from the cup-shaped wall 59 hav-' ing a head portion 60 cooperable with a smaller inverted cup 61 as a stop member limiting the extent of movement 7 of the bellows 58. The bellows 58 is urged toward a co m-' V 3 pressedpositiomby a 'sprin'g'62 within the power element casing 57 A- capillary tube 63 opensinto and is her-e metically sealed in the power element casing 57 and carries on its other end the bulb element 9 shown in Fig. 2. Thefbulbielement.9;;capi1lary. tube:63 andsth'ei space en closed between the power element casing 57 and the bel-L lows$are filled-with. atemperature responsiveifiuidfor thermal response- The power. element casing 57 also carries=la= guide: :ri'ng: 641-which. guides an: enlarged: portion of the thru'strod-53 and-which carriesa plurality of damp-' in-g springs' 65- frictionally engagable with'..said. enlargedrod-portionto' reduce the response to sudden minor temperature changes. Onithe 'oth'erleglof the T-shaped casing. 48 thereis; threadedly. carried a tubularisupporting casinga66' which-carries onrits end a: temperature respon siverpower element 6.7.. The power'element 67 comprisesa cup-shapedcasing-z68'having secured and sealed thereina pressure:movable-bellows 69 havinga cup-shaped end wall.70. .Therbelliows en'd wall..70 receives and has sealed therein-therother end-of the' thrust. rod 54 and has a rod portion. extending withinfttheicasing 68 having a head portion; 71; cooperable': with the inverted cup-shaped member 72 as:.a.'stop.. determining theextent of movement of. the: bellows 69. There is. also providedla capillary tubing 73 sealedi inand openingthroughthepower ele ment casing168and carrying at its: other end thetempera ture'responsivezbulb elementlt) as shown inFig. 2.- The powerv element.67-, capillary tube 73and-bulb element lll are :filled with a temperature responsive fluid fortemperature'zresponseof this valve. The bellows 69 is urged t'owardcollapsed position by a spring 74-positioned between" the powerelement'casing 68 and the-bellowsen'd wall 70.- The power elementsupporting casing 66 also carries rigid therewitha :cup-shaped'supporting wall.75 having a central. aperturel therethrough: through which. extends the thrust. rod 54. 'Within'the supporting casing66iand surrounding, the: thrust rod54 there is provided a spring 76 seatingat:-0ne end on-the wall.75. 'andatits other end againsta threadedly adjustable abutment .member 77 carriedotrthe'rod 54; The spring 76 urges the rod.54- in a' direction. opposing the-power element bellows 69. The

abutment member 77 is. threadedly adjustable: along: the

. rod..5.4:toI determine-the extentv ofcompression of the:

spring 76 andithe force 'whichfis .exertedthereby against the.rod-.54. Thersupporting casing66 has anaccess. open ing provided. therein through a fitting- 78 closed by'a threaded plugmember 79 andproviding access to the abutment member-:77 forradjustment of 'the. spring 76.

Operation A's issh'ownin Fig. 2lthe valve 8'is connected in the .in-. let'li'n'eto the condenserZ'to control flow of cooling water thereto. The valve is arranged to operate on the diiferential'of'inlet andoutlet temperature of the cooling water flow'in'gto and from the condenser and is controlled by response of. the bulh elements 9' and 19 through their power elements 56land' 67 respectively. The. pressure responsive bellows-39l is=responsive to the pressure on the discharge or outlet side'of'the compressor 1 through conduit '11 which would beconnected tothe inlet fitting38.

Thev'alve 8 as connected in thesystem shown in Fig.

2 has itslinlet l'3lconnected to the source of cooling water andit'soutlt 14 connected 'tothe condenser 2. The valve as shown in:Fig. 1. is a: pilot operated valve operated by pressu're'ofthe cooling water flowingthrough the valve. When" the pilot valve33'. is in the position shown in Fig. 1

closin'gg'thevalve port 32, the pressure ofwater in the inlettothevalvecasing 12 and within the tubular casing projection 18" is equalized through the orifice 19 in the vaive piston19jandthe spring 26 is thus able to hold the pistont19:in theposition shown with the valve disc 21 closingithe valve port 16. When the valve member 33 is movedito' open thevalveport 32' water from within the casing'gprojection 18' and'valve piston-19 is able to discharge through the aperture 30', valve port 32, chamber 28anddischargepassageway31 causing a pressure differentialacro'ss'thepiston19which will move thepiston 19 against the'force'of the spring 26 and open the valve port 16 for"fiow "of cooling water to the condenser. The pilot valve member33 which controls the operation of the main valve isjoperated by thetwo power elements 56 and 67 and? also by the pressureresponsive bellows 39. The valve-- member '33'-maybe opened fby rocking 'rnovement of-thelever-46 whih may becaused by'the resultant force of the two power elements 56 and 67. The power element 67 "iv arranged" for'responseto higlr'temperature and the power element 56 to low temperature. The spring 76 determines the amount ofdifierence of force exerted by the power elements 56 and 67 required to move the lever 46 to operate the pilot valve 33. If the spring 76 is set to require a temperature difference of say 20 F., thenzaslongza's the diflerence oftemperature of-cooling water between the inlet'a'nd'outlet of'thei condenser exceeds 20 F., the lever 46 will be moved to open the pilotwalve 33 andl cause the main valveto be opened Whenever the temperature/ difference drops belo'w- 'th'e set value ofsay 20 F., the power elements 56 and 67 and the springs 76 and 42 will cause the lever 46 to. rotate and move the valve member 33 '-toward a closed position and thus cause the main valve-to be closed. The pressure responsive bellows 39"is provided to operate the pilot valve member 33 to cause the same to be opened and permit cooling waterto flow to' the condenser" whenever a p'redetermined maximum pressure is produced by the-compressor 1. Thus; if the temperature 1 dilferen'ce 5 between theinletland outlet of-the condenser ha's dropped b'elow 20F. and the fiowfof cooling waterhasbeen-cut 'ofi: to the condenser; and if an excessive pressure is produced by the compre'ssor 1,- the bellows '39willioperate directly on: the valve:member '33 r and override the force of the 't'emperatureiresponsive :p'ow'er elements to cause the valve to open'iand' supplythe required cooling water to the condenser. It should be noted that the pressure responsive valve for controlling flow-of coolin'g water to a refrigerant" condenserwvhich will resp'o'nd accurately to the temperature difference across the condenser and thus provide'a great economy in the supply of cooling water-butat the same: timewill provide safety-of'operation by having-in corporated-therein a'pressure responsive override arrangement which will cause the water control valve to b'e opened whenever an excessive refrigerant line pressure occurs.

Although there has been described herein only one ens-" bodimentofthe invention, it will be obvious to those skilled-in the art that numerous minor changes*orcolor-- able variations therefrom might be made without depart-- ing -from the scope and intent" of this invention which is intended tobe limited only by the appended claims.

Having thus described the invention, what is claimed anddesired to be secured -by Letters Patent of the United Statesis:

1. In a valve of the character described; a main'valve casing having an inlet, an'outlet, a valvepo'rnand a valve chamber. overlying said port; a main valve:member"movable in said' chamber to openand to close said port,,a= pilot valve casing carried on saidmain valve casing and closing said valve chamber, means including said valve casiugs forming a passageway extending from said valve chamber to the outlet of said main casing, a valve seat in said-"pilot casing forming a valve port controlling said passageway a pilot valve member movable'insaid'pas sage way to open and to'close said last-named valve port; thermostatic means carried. onsaid pilot casing-'and'connested toand operable to move said pilot valvemember; and'pressure responsive means carried'on said pilot casing andconnccted to 'said pilot valve member'in opposed'relation to saidthermostati'c means and operable to override the same to opensaid pilot valve.

2. In a valve of the character described; a main valve casing-having an inlet, an outlet, a valve port, and 'a valve'chamberoverlying said port; a main valvemember movable insaid chamber to openandflto closesaidport, a pilot valve. casing carried on said mamvalve casingv and closing said valve chamber, means. including said static power elements carried on said pilot casing and connected to and operable to move said pilot valve member in accord with a temperature differential, and pressure responsive means carried on said pilot casing and connected to said pilot valve member in opposed relation to said thermostatic means and operable upon occurrence of a predetermined pressure to override the same to open said pilot valve.

3. In a valve of the character described; a main valve casing having an inlet, an outlet, a valve port, and a valve chamber overlying said port; a main valve member movable in said chamber to open and to close said port, a pilot valve casing carried on said main valve casing and closing said valve chamber, means including said valve casings forming a passageway extending from said valve chamber to the outlet of said main casing, a valve seat in said pilot casing forming a valve port controlling said passageway, a pilot valve member movable in said passageway to open and to close said last-named valve port,

thermostatic means comprising a pair of remote responsive thermostatic power elements carried on said pilot casing and connected to and operable to move said pilot valve member in accord with a predetermined differential of temperature of response, adjustable spring means resisting operation of said thermostatic means and determining the differential required for valve operation, and pressure responsive means carried on said pilot casing and connected to said pilot valve member in opposed relation to said thermostatic means and operable upon occurrence of a predetermined pressure to override the same to open said pilot valve.

4. In a valve of the character described; a main valve casing having an inlet, an outlet, and a valve port; a tubular projection on said casing forming a valve chamber overlying said port, a valve member closing said port and reciprocally guided in said chamber, said valve member being operated by inlet pressure and having a bleed aperture for equalization of pressure, a spring in said chamber urging said valve member toward closed position, a pilot valve casing carried on said main casing and having a valve seat member and valve port dividing the same into first and second chambers, said pilot valve casing having passageways connecting said first chamber with said valve chamber and said second chamber with said main valve outlet, a pilot valve member guided in said first chamber and having a stem extending into said second chamber, said pilot valve casing having an opening overlying said first chamber, a pivot member positioned over said open ng, a lever member pivoted on said pivot member and having its lower end engaging said pilot valve member for operation thereof, a flexible bellows member secured to said pivot member and said lever member to seal said first chamber against leakage, a T-shaped casing carried on said pilot valve casing and securing said pivot member in position, fluid expansive power elements carried on opposite legs of said T-shaped casing and having remote responsive bulb elements, said power elements having thrust rods oppositely and operatively engaging said lever member to operate said pilot valve in accordance with the diflerential of temperature between said power element bulb elements, an adjustably supported spring positioned in opposition to one of said power elements to determine the diiferential of temperature required for pilot valve operation, a pressure operated bellows closing the end of said second pilot valve chamber and engaging said valve stem, a cup-shaped cover member enclosing with said bellows a pressure responsive chamber and having an inlet fitting, and said bellows being operable in response to predetermined excessive pressure to override the force of said power elements and move said pilot valve member to an open position.

5. In a control valve, a valve casing having a passageway therethrough with a valve port, a valve member in said casing and cooperable with said port, said casing having a wall opening alined with said port, fluid pressure responsive means closing said opening, a valve stem interconnecting said responsive means and said valve mem her, said casing having a side wall opening, a lever 0peratively engaging said valve member and extending through said side wall opening, a housing carried by said casing and having an opening through which said lever extends, a thrust rod in said housing and engaging said lever, a thermostatic power element carried by said housing and engaging said thrust rod to actuate said valve member, and a cover member enclosing with said responsive means a pressure responsive chamber, said cover member having an inlet opening to said chamber for connecting said chamber to a source of fluid pressure, and said responsive means being operable in response to a predetermined external pressure supplied through said cover member opening to override the force of said power element and move said lever to actuate said valve member.

6. in a control valve, a valve casing having a passageway therethrough with a valve port, a valve member in said casing and cooperable with said port, said casing having a wall opening alined with said port, fluid pressure responsive means closing said opening, a valve stem interconnecting said responsive means and said valve member, said casing having a side wall opening, a lever operatively engaging said valve member and extending through said side wall opening, a housing carried by said casing and having an opening through which said lever extends, a pair of thrust rods in said housing engaging said lever in opposed relation, a pair of remote responsive power elements carried by said housing and engagin said thrust rods to actuate said valve member, adjustable spring means cooperable with one of said power elements to determine the condition of said power elements required to open said valve, and a cover member enclosing with said responsive means a pressure responsive chamber, said cover member having an inlet opening to said chamber for connecting said chamber to a source of fluid pressure, and said responsive means being operable in response to a predetermined external pressure supplied through said cover member opening to override the force of said power elements and move said lever to actuate said valve member.

7. a control valve, a valve casing having an inlet and an outlet and a valve port therebetween, a valve member guided in said casing for movement relative to said valve port, said casing having an opening adjacent said valve member, a pivot member positioned over said opening and supported on said casing, a lever member pivoted on said pivot member and having one end engaging said valve member for operation thereof, a flexible bellows member secured to said pivot member and said lever member to seal said opening against leakage, a T-shaped casing carried on said valve casing and securing said pivot member in position, fluid expansive power elements carried in opposite legs of said T-shaped casing and having remote responsive bulb elements, said power elements having thrust rods oppositely engaging the other end of said lever member and operable to move the same according to the differential of temperature between said bulb elements, an adjustably supported spring in said T-shaped casing positioned in opposition to one of said power elements to determine the differential of temperature required to move said lever, said casing having a second opening on the opposite side of said valve port from said valve member and aligned therewith, a pressure responsive bellows closing said second opening, a valve stem interconnecting said bellows and said valve member, a cup shaped cover member enclosing with said bellows a pressure responsive chamber and having an inlet opening, and said bellows being operable in response to a predetermined excessive pressure to override the force of said power elements and move said lever to open said valve.

References Cited in the file of this patent UNITED STATES PATENTS 1,638,053 Muller Aug. 9, 1927 1,925,281 Replogle Sept. 5, 1933 2,919,724 Otto NOV. 5, 1935 2,057,101 Kagi Oct. 13, 1936 2,060,589 Otto Nov. 10, 1936 2,356,261 McGrath Aug. 22, 1944 2,410,795 Dillman Nov. 5, 1946 2,551,758 Newton May 8, 1951 

